Technical Field
The present disclosure relates to an optical spacer. More particularly, the present disclosure relates to an annular optical spacer with annular protruding structures.
Description of Related Art
Due to the popularity of personal electronic products and mobile communication products having camera functionalities, such as smart phones and tablet personal computers, the demand for compact lens assemblies has been increasing, and the requirements for high resolution and image quality of present compact lens assemblies increase significantly.
An optical spacer is generally used to provide an optical space between any two lenses in a lens assembly. A surface property of the optical spacer relates to an effect of suppressing unexpected lights. Accordingly, an image quality of the lens assembly is influenced by the surface property of the optical spacer.
A conventional optical spacer is typically manufactured by an injection molding method. The optical spacer has a smooth and bright surface, which is featured with high reflectivity. As a result, the conventional optical spacer cannot suppress the unexpected lights.
Another conventional optical spacer is provided for suppressing the unexpected lights. The conventional optical spacer is atomized with a surface treatment, so that a reflectivity thereof is reduced. However, the effect of suppressing unexpected lights is still limited. Therefore, the conventional optical spacer cannot satisfy the requirements of high-end optical systems with camera functionalities.
Given the above, how to improve the surface property of the optical spacer for improving the image quality of compact lens assemblies has become one of the important subjects.